Barros, António S.

Oliveira, Carla Maria

Silva Ferreira, António César

Silva, Artur M. S.

English

Repositório Institucional da Universidade Católica Portuguesa

Phenolic Compounds in Wine: Primary Substrates for Oxidation Carla Maria Oliveira,1,2* Artur M. S. Silva,1 António S. Barros1 and António César Silva Ferreira2,3!!1. Departamento de Química & QOPNA, Universidade de Aveiro, 3810-193 Aveiro, Portugal!2. Escola Superior de Biotecnologia, Universidade Católica Portuguesa, Rua Dr. António Bernardino de Almeida, 4200-072 Porto, Portugal!3. Stellenbosch University, Private Bag X1, Matieland, 7602, Stellenbosch, South Africa!* Corresponding author: cm.dias@ua.pt/ cmdias@aesbuc.pt!Escola Superior de Biotecnologia!1,2*, 1,!!!!!!Phenolic Compounds: Primary Substrates for Oxidation Wine Oxidation!O2 HO2λ  OOHROHOHRFe2+ Fe3+ Quinone Semi-quinone Radical H2O2  OHOHROOHR +		Quinone Fe2+ Fe3+ Fenton Reaction HOλ   Semi-quinone Radical Reduced transition metal ions, essentially iron(II) and copper(I) are required!!Objectives:!The identification and quantification of phenolic compounds related with the wine oxidation process using a forced aging protocol!The expression between identified phenolic compounds and the antiradical activity giving by ABTS methodology!The influence of oxygen supplements in the consumption of phenolic compounds!Chemical oxidation of wine begin by the oxidation of polyphenols containing a catechol or a galloyl group E	  (mV)	  815	   Coumaric	  acid	  	  800	   Vanillic	  acid	  	  680	   Syringic	  acid	  	  670	   Ferulic	  acid	  	  500	   Ru4n	  	  470	   Gallic	  acid	  	  460	   Caffeic	  acid	  	  425	   Querce4n	  	  420	   Catechin	  	  O.	  Makhotkina,	  P.A.	  Kilmar;n	  /	  Analy;ca	  Chimica	  Acta	  668	  (2010)	  155–165	  (an ortho-catechol) !Caffeic acid and its derivatives!OHOHOHOHOOHOHOHOOH OQuercetin!(+)-Catechin !Gallic acid !and its derivatives!OHOHOHOHO(a galloyl group)!HOOHOHOOHOHHPLC/DAD and antiradical activity analysis!•  Forced Aging Protocol - 42 Days!Samples were taken and analyzed weekly Treatment II:!2 times saturated!(F2)!Treatment I: !no oxygen addition!(F1)!Treatment III:!3 times saturated !(F3)!White wine (pH = 3.2): 4 oxygen regimes !Treatment IV:!saturated !every sampling point (F4)!V = 1000 ml!T = 20 ºC!V = 1000 ml!T = 30 ºC!V = 1000 ml!T = 40 ºC!V = 1000 ml!T = 50 ºC!V = 1000 ml!T = 20 ºC!V = 1000 ml!T = 30 ºC!V = 1000 ml!T = 40 ºC!V = 1000 ml!T = 50 ºC!V = 1000 ml!T = 20 ºC!V = 1000 ml!T = 30 ºC!V = 1000 ml!T = 40 ºC!V = 1000 ml!T = 50 ºC!V = 1000 ml!T = 20 ºC!V = 1000 ml!T = 30 ºC!V = 1000 ml!T = 40 ºC!V = 1000 ml!T = 50 ºC!OHOHOHOE	  (mV)	  470	   Gallic	  acid	  	  460	   Caffeic	  acid	  	  420	   Catechin	  	  y = -0.0091x + 3.2598 y = -0.0136x + 3.2759 2.25 2.50 2.75 3.00 3.25 3.50 0	   10	   20	   30	   40	   50	  Concentration (mg/L) Storage Time (days) F1_20ºC_Catechin F4_20ºC_Catechin RRC = 1.5 y = -0.0041x + 3.2507 y = -0.0052x + 3.1905 2.50 2.75 3.00 3.25 3.50 0	   10	   20	   30	   40	   50	  Concentration (mg/L) Storage Time (days) F1_20ºC_Cafeic acid F4_20ºC_Cafeic acid RRC = 1.3 y = -0.0182x + 4.9464 y = -0.0289x + 4.9713 2.00 3.00 4.00 5.00 6.00 0	   10	   20	   30	   40	   50	  Concentration (mg/L) Storage Time (days)  F1_20ºC_Gallic acid F4_20ºC_Gallic acid RRC = 1.6 no oxygen addition!oxygen addition!HOOHOHOOHOHOHOHOHOHOPhenolics with lower oxidation potentials  OHOHOH3COOHOCH3OHOE	  (mV)	  815	   Coumaric	  acid	  	  680	   Syringic	  acid	  	  0.50	  0.60	  0.70	  0.80	  0.90	  1.00	  0	   20	   40	   60	  Concentration (mg/L) Storage	  Time	  (days)	  F1_20ºC_Coumaric	  acid	  F4_20ºC_Coumaric	  acid	  2.50	  3.00	  3.50	  4.00	  4.50	  5.00	  5.50	  6.00	  0	   20	   40	   60	  Concentration (mg/L) Storage	  Time	  (days)	  F1_20ºC_Syringic	  acid	  F4_20ºC_Syringic	  acid	  no oxygen addition!oxygen addition!Phenolics with higher oxidation potentials  No significant decrease was found More	  oxidized	  wines ! Less	  oxidized	  wines !PCA illustrate the global chemical differences of 15 compounds identified at 280 and 320 nm !PCA scores analysis: First versus second principal components (75%).!!Results have showed that wines with higher levels of phenolic compounds have higher antiradical activity.  PLS can be used to determine the expression between antiradical activity giving by ABTS and the 15 phenolic compounds identified!However, in the presence of oxygen, phenolics oxidation undergoes further oxidation reactions.!Conclusion	A wine oxidative process classification can be achieve by both phenolics quantification and ABTS antiradical activity.!During the process of non-enzymatic oxidation the oxidative processes begin by the oxidation of polyphenols containing a galloyl group or an ortho-diphenol like gallic acid, (+)-catechin and caffeic acid;!Moreover, oxygen supplements increase the consumption of these easily oxidizable phenolic compounds that undergoes further oxidation reactions;!Thank You	

Phenolic compounds in wine: primary substrates for oxidation

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Phenolic compounds in wine: primary substrates for oxidation

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